Drop the powerfist. instead take a bolt pistol, or if you insist on extra HQ power, lightening claws are pretty good on an HQ. IF and ONLY IF you utterly refuse to ditch the powerfist, field a thunder hammer instead, this is because the only time it would be useful to use a powerfist is on something you cannot easily wound. Therefore, it cannot be instent deathed by a powerfist, nor a thunder hammer, BUT the thunder hammer makes it strike last in CC.